So, by making the opening ceremony rain free, they've all but guaranteed
the rest of the event to have lower air quality. How do I know this?

I've lived in Beijing during this time of year and the air on morning/day after a rain event is always much nicer than it was the day before.

So why is it so humid in Beijing? The prevailing wind direction from most weather patterns that affect the city is onshore (wind blows from the sea to the land.) During summer this brings lots of hot moist air from out over the ocean, over the land until it meets the mountains that border Beijing, trapping it. About once every 2 weeks they get a westerly wind pattern and all that crap gets blown out to see - clear skies usually last less than 48 hours.

I'm sure the only people who are surprised about the condition of the air in Beijing are the IOC folks that haven't spent any real time in the city and lapped up whatever the Chinese told them. The Chinese people won't be, anyone who has been to Beijing won't be, athletes maybe (because they've been duped by the IOC.)

So the buildup of bad air continues and one is left to wonder if the Chinese authorities will insist on playing God (and make things continually worse) for the entire event or will let nature look after itself.